Reinforcing a wave guide

[David Brown]

I have been hearing good things about the audio quality of the JBL 308P MkII 8" 2-Way Powered Studio Monitor speaker which is largely attributed to its waveguide. Some people feel that the wave guide is too thin and flimsy though and to reduce resonance they are reinforcing it on the inside with epoxy. Apparently you have to be careful to do this in several stages because, if too much is used at once, the epoxy can heat up as it cures and then burn through the plastic. I was wondering if PL adhesive might be a good substitute for epoxy in this application? It doesn't heat up as it sets and it seems to get quite hard. I don't know if there are any resonance issues with it though? I am only writing about this on the forum because I don't believe there is a Fitzmaurice small near field studio monitor design. I wish there was, but as I understand it, horn loading requires a larger enclosure size to be effective. I have built some TLAHs and some SLAs, but as great as they are, they are not intended for near field studio monitoring.

[Bill Fitzmaurice]

I'd use some of this:
https://www.amazon.com/dp/B07QY1X35P/re ... s9dHJ1ZQ==

Even better, drive around your neighborhood looking for roofers putting a roof on a house. They use a similar product under shingles. They'll give you enough scraps to do the job for free.

[David Brown]

Thanks for this Bill. Would you use PL adhesive or something else to bond the damping material to the wave guide?

[Tom Smit]

Thanks for this Bill. Would you use PL adhesive or something else to bond the damping material to the wave guide?

I believe it is self-adhesive, after reading the info given in the link that Bill shared.